You are not logged in.
An Oct. 21 letter from Congress to O'Keefe told NASA to stop spending so much energy on OSP. Several congressman supported Zubrin in the senate committee hearing this morning, although I missed most of the hearing. Zubrin's testimony is on the website. He condemned OSP and called for $60 million for two separate groups to design a Mars mission, He has called for that before but they are probably more receptive now.
http://www.spaceref.com/news/viewnews.html?id=892
"The final result may be a presidential announcement of the new space goal in a national address at Kitty Hawk, North Carolina on December 17, 2003, the 100th anniversary of the Wright Brother's first heavier-than-air powered flight.
According to sources familiar with the White House review, the current plan-subject to change at any time the sources say-is for a final recommendation to the president by November 30th "or shortly thereafter", followed by insertion of the goal into the speech and development of timetables and supporting budgets. "
"As of late October, sources indicate that a central recommendation is likely, but not certainly to be resumption of manned lunar flights to develop advanced technologies that can support U.S. astronauts working beyond Earth orbit to not only the Moon, but eventually on near-Earth asteroids and Mars. "
"In an early phase of the meetings, manned Mars expeditions were considered too expensive and risky to adopt as a central goal for the civil space program. But Bush is being urged to factor in future interplanetary manned flight capabilities as part of the justification for a return to the moon."
Offline
In light of a major policy change, it would be expedient to delay OSP and re-scope it to support both ISS and lunar needs. My belief is that Boeing and LockMart should build two different OSPs and should retain ownership of both. The Boeing design, based on Boeing North American's Apollo, would be better suited for the moon. The LockMart design, based on Martin's old X-24, would be tailored to serving as a manned ISS ferry.
Going to the moon should not be viewed as a setback for us die-hard Mars junkies. Although the moon is different from Mars, it is still an arena for maturing the technologies that will take us to Mars, including the booster rockets, life support, and nuclear power that are essential for Mars exploration to succeed.
Who needs Michael Griffin when you can have Peter Griffin? Catch "Family Guy" Sunday nights on FOX.
Offline
Hmmm back to the Moon ey?
I suppose that it wouldn't be a totally bad idea... test an ice-eating water/fuel/oxygen refinery, TransHab modules, life support gear etc. within easy(er) range of home. If Nasa intends to do anything there besides play golf or pick up more rocks though, they will have to build a base of some sort wouldn't they? And in that case, Nasa will need to build a medium lander module (20 ton minimum payload), which might be reuseable if fueled on the surface from ice, which could act as a Earth/Moon tug for flying over medium-sized stuff launched on heavy lift EELVs. OSP could mate up to it, fly to Lunar orbit, down, and back up just being another payload.
As such, OSP need not be a capsule at all, since the wings won't be a liability in a vacuum, and the reuseable lunar tug would have to break into Earth orbit for the next cargo anyway. This would save a greaaat deal from having to build TWO different OSP's.
I am hesitant to suggest using a Shuttle-Derived megabooster for Lunar cargos, because not only would you suffer a huge mass penalty to launch a cargo directly to Lunar orbit that is just fuel needed to get you there, but you have to be able to accuratly LAND the stuff when you get there, which would be tough to build a lander able to haul 40-60+ tons.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
The Michael Duke proposal, A Lunar Reference Strategy (located on David Portree's Romance to Reality page) used a "lunar based vehicle" or LBV that was refueled with hydrogen and oxygen made from lunar ice at the south pole and able to land about eight tonnes of cargo. Possibly Duke had an LBV that eventually could land more in mind, though. He was proposing an initial space shuttle launch of 25 tonnes to low earth orbit; nine tonnes of that would be a solar-electric vehicle, complete with xenon prolellant, which would push the rest to the moon; of the remaining sixteen tonnes, eight would be cargo to land of the moon and eight would be the LBV, complete with initial landing fuel. I think the masses would work out something like this:
Solar Electric Vehicle dry mass: 4.5 tonnes
Xenon propellant 4.5 tonnes
LBV dry mass: 1.5 tonnes
LBV initial LOX/LH2 fuel: 6.5 tonnes
payload: 8 tonnes
But the SEV and LBV would be reusable. If you bring the SEV back to low earth orbit, the next 25 tonnes could include 5 tonnes of xenon and 20 tonnes of payload. When the payload gets to the vicinity of the moon (the Lagrange point), the LBV flies up twice, docks with half the cargo, and lands ten tonnes each time.
I suppose a larger LBV would be relatively easy to build. The basic formula for figuring out the LBV seems to be that the fuel mass plus dry mass equals the payload mass landed. Thus to land eight tonnes, you need about eight tonnes of fuel plus structure; and to get the eight tonnes of fuel to the cargo in high lunar orbit you need another roughly eight tonnes of fuel (a bit less, actually, because its the same structual mass). So an LBV would take off from the moon with sixteen tonnes of lunar-made fuel, reach orbit with eight tonnes of fuel, rendezvous with eight tonnes of payload, and land it on the moon. To land twenty tonnes of cargo you'd have to take off with about forty tonnes of fuel and would have twenty tonnes of fuel at the lagrange point to bring the twenty tonnes of payload to the lunar surface.
The same system could be used to push twenty tonnes to Mars (which is not enough mass for a vehicle with crew, but is enough for a cargo vehicle). You'd launch 25 tonnes with an EELV to low earth orbit, including five tonnes of xenon fuel; the solar electric vehicle would already be there, would dock and push the payload to the lagrange point between the Earth and the moon; an LBV would fly up from the moon and meet it, and use some of its eight tonnes of fuel to push the twenty tonnes to trans-Mars injection (which takes much less delta-vee than landing on the moon from Lagrange); then the LBV would either be expended or it would retain enough fuel to fly itself back to Lagrange. It's a pretty nifty system for getting cargo to both the moon and Mars cheaply.
-- RobS
Offline
Hmmm sounds interesting, and I do like the idea of having a Lunar-orbit staging area at a Lagrange with a ready supply of LH2. A couple of concerns though...
The solar ion tug, or for that matter anything ion-drive powerd, will be much too slow to fly a human or time sensitive payload (e.g. living material, speciality radioisotopes) up to Lunar orbit. Plus, we don't have alot of experience building a giant ion drive able to push 8-20 tons very fast.
Instead in the near-term, we start with a pair (one for backup manned return) of conventional cryogenic fuel tugs powerd by a SSME or RL10 type engine, since the tug won't ever have to store its fuel for very long with the short Earth/Moon trip times.
Since it isn't easy to land a large mass on the Moon, payloads should be limited to 20 tons, so only EELV class launchers will be really required. Two conventional LOX/LH tug would be launched fueled into LEO followed by the fueled lander and the propellant plant in four launches, flown to Lunar orbit, and the lander would bring down the fuel plant and refuel itself. Back up to Lunar orbit to refuel a tug, which goes back to Earth to pick up another waiting 20 tons cargo and either return with remaining fuel or be fueled by another EELV launch and back to the Moon to mate up with the LBV... etc.
In the not-so-midrange future, as hopefully a "Nerva-II" would be built (or even a GCNR, woohoo!) then might push multiple 20-ton or SDV scale payloads to the Moon, then there would be no more excuses to start setting up shop perminantly on Mars.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
Offline
The solar-electric (ion) vehicle (SEV) is several hundred times larger than the existing ion powered vehicles, so it will require special development, but it should not be hard to develop. Duke calculated it could be had for half a billion bucks. The SEV would take six months to get cargo to Lagrange 1. Astronauts would fly up quickly in a reusable 8-tonne vehicle based on the X-38 lifting body, pushed by a chemical stage. It needs to be about 8 tonnes because the lunar-based vehicles are designed to land eight tonnes of cargo on the moon; they'd land a manned vehicle instead of cargo. The LBV would then be refueled while the astronauts carry out their surface mission, and then the LBV would launch the manned vehicle back to Lagrange, where it would then coast back to earth, aerobrake, and rendezvous with ISS (or land on Earth). I think a 24-tonne launch could put an 8-tonne manned vehicle and a 16-tonne chemical stage into orbit, and the latter can push the former to Lagrange.
Even more interesting, Duke notes that the system can provide the fuel needed to lift the manned vehicle to lagrange as well. The LBV has the capacity to hold about sixteen tonnes of liquid hydrogen and oxygen. These could be used to lift sixteen tonnes of ice to lagrange; the LBV then would land itself back on the moon. The ice could be attached to an aeroshield and incrementally aerobraked to low earth orbit, where it could be converted into hydrogen and oxygen fuel to push the next manned vehicle back to Lagrange. Or two LBVs could fly to lagrange, each with eight tonnes of LOX and LH2. If the ability to transfer fuel is developed, one LBV could be filled up with sixteen tonnes of propellant and attached to an aeroshield, and could fly to LEO; it would fly back to lagrange 1 with the manned vehicle.
This is the cool thing about the proposal, then. Three EELV launches (he said shuttles, but that's probably out now!) could launch three solar-electric vehicles, three LBVs, and three eight tonne cargos; the latter three could include one or more eight-tonne automated fuel making plants, an eight-tonne inflatable hab, and maybe some supplies. The eight-tonne fuel making systems can make, he says, thirty-two tonnes of fuel per year each (and in an email to me, he said he now thinks they could make more). Once the system is up and running, every EELV/shuttle launch from Earth could send three astronauts to the moon. An eight tonne vehicle would require sixteen tonnes of LEO fuel, requiring another sixteen tonnes of fuel to lift it to Lagrange; it would require eight tonnes of fuel at Lagrange, which would require another eight tonnes of fuel to lift it to Lagrange; and eight tonnes of fuel would be need to launch the manned vehicle from the lunar surface back to Earth. Thus each three-person flight requires 56 tonnes of lunar-manufactured fuel. You'd need two eight-tonne units on the moon to make that annually. For two flights per year, you'd need four units. You'd also need three LBV flights to support each crewed flight.
You can see how useful this idea is for flying to Mars, because the solar-electric vehicles, Duke notes, are one third the size of what is needed for a Mars mission (based on the mass of the Design Reference Mission), they can lift the Mars mission to the lagrange point which is 95% or so out of the Earth's gravitational field, and the moon-fueled LBVs can provide the rest of the rocket fuel and engines you need. This is the basis of my Mars-24 thread of last fall, and it, in turn, was the technological basis of the "Mars Frontier" novel that is now partially on the New Mars main page.
--RobS
Here's the link to Portree's summary of Duke's proposal:Duke proposal
Offline